Electrical power distribution systems distribute electrical power over great distances at high voltages to minimize conductor sizes and compensate for unavoidable transmission losses. When the power is used, it is typically used at much lower voltages than those at which it is distributed. This requires the transformation of the power from a higher voltage to a lower voltage, by means of an electrical transformer. Therefore, for this purpose and many others, there are a great many electrical transformers in service.
Many of these transformers are filled with oil for the purpose of cooling and insulation. As a transformer ages, and as it is subjected to high loads, varying loads, and severe environmental conditions, various components within the transformer will necessarily begin to degrade or eventually to fail. In addition, some defect or misuse can cause failure of some components of the transformer. As components degrade or fail, or as other undesirable processes occur within the transformer, various chemicals can be created in or released into the oil in the transformer. These chemicals can be in the form of dissolved gases, or they can react with other chemicals to form dissolved gases in the transformer oil.
It is well known to periodically sample transformer oil to analyze the dissolved gases to detect the aging or failure of various components, or to detect other processes that might take place within the transformer. The purpose of this analysis is to determine when maintenance, repair, or even replacement of the transformer is necessary. The existence in the transformer oil of a given gas in a given concentration might indicate failure of paper or some other insulator, or it might indicate electrical arcing between components, or it might simply indicate a harmless effect of normal operation. Detecting a single gas dissolved in the oil will seldom reveal a complete and accurate picture of what is happening in the transformer. In order to accurately identify the occurrence of a particular type of problem in the transformer, it is usually necessary to detect the presence and the concentrations of a number of known gases in the oil.
Currently, sampling and analysis of transformer oil is commonly done by sending personnel out to the transformer, drawing a sample of the oil, taking the sample to a laboratory, and running analysis by methods such as gas chromatography to detect the presence and concentrations of the dissolved gases in the oil. In view of the large number of transformers in service, this requires a very large investment in man hours and equipment. It also affects the load capacity of the distribution system involved, and it requires numerous personnel entries into substations and other hazardous areas. Further, information on the dissolved gases present in a given transformer can only be obtained at infrequent intervals, for reasons of economy. Currently known systems are too expensive to be permanently installed on a single transformer, and they would be inherently inaccurate because of an inability to correctly interpret the status of a transformer based on the information that would be available from currently known sensors, without the presence of an operator.
It is an object of the present invention to provide an apparatus for the qualitative and quantitative analysis of the dissolved gases present in a fluid such as the oil in a transformer on a frequent or continuous basis, without the presence of an operator, using inexpensive sensors. It is a further object of the present invention to provide an apparatus for the qualitative and quantitative analysis of the dissolved gases present in transformer oil, that is easy and inexpensive to manufacture and use.